The present application relates to and incorporates herein by reference Japanese Patent Applications No. 2000-321160 filed on Oct. 20, 2000, and No. 2001-181278 filed on Jun. 15, 2001.
The present invention relates to a starter, in which a pinion shaft integrally moves backward and forward with a pinion.
In a conventional starter disclosed in JP-A-2000-9003, a pinion shaft is integrated with an inner surface of a one-way clutch and a pinion is fitted to the pinion shaft in a rotation-restricted manner. The pinion shaft is integrally pushed forward with the pinion by using an attracting force (pull-in force for pulling a plunger) of a magnet switch. As shown in FIG. 9, a clip 100 is fitted in a circumferential recess 120 provided on the pinion shaft 110 to restrict the pinion from moving in an axial direction.
However, a width of the circumferential recess 120 is set larger than a thickness of the clip 100 for installing the clip 100. Therefore, a clearance remains between the clip 100 and the pinion 130 so that the pinion 130 becomes unsteady against the pinion shaft 110. In this case, the pinion 130 is abraded by fretting due to small vibrations. As a result, a harsh chattering sound is generated at the time of starting an engine. Also, by the vibrations of the pinion 130, an abrasion of a ring gear which meshes with the pinion 130 is likely to increase. Further, right after the engine starts, if the pinion 130 is turned by a ring gear at high speeds, the clip 100 is expanded by a self-centrifugal force and disengaged from the recess 120.
In view of the foregoing problems, it is an object of the present invention to restrict vibrations of a pinion against a pinion shaft in a starter, in which the pinion is integrally pushed forward with the pinion shaft at the time of starting an engine.
According to one aspect of the present invention, a pinion is fitted on a pinion shaft such that a rear end surface of the pinion is pressed against a step provided on the pinion shaft while a front end surface of the pinion is pressed backward through a restricting member such as a detent ring. Since the pinion is restricted from moving in an axial direction by being pressed against the pinion shaft, the vibrations of the pinion is decreased.
Further, the restricting member fitted in a recess of the pinion shaft has a tapered surface on a front side inner periphery thereof. Also, a front rising wall defining the recess has a tapered wall so as to correspond to the tapered surface of the restricting member. When resiliency of the detent ring contracting radially inward is applied to the tapered wall defining the recess, a component force of the resiliency pressing the pinion axially backward is generated. Thus, the pinion is press-fitted against the step of the pinion shaft. In addition, a cover is provided for restricting the detent ring from expanding in the radial direction and being disengaged from the pinion shaft when the pinion shaft rotates at high speeds.
According to another aspect of the present invention, a pinion shaft has a thrust receiving wall for restricting a pinion from moving axially backward. The pinion is fitted on the pinion shaft such that a rear end surface of the pinion adjacently faces the thrust receiving wall of the pinion shaft in an axial direction. When the pinion meshes with a ring gear of an engine at the time of starting the engine, the rear end surface of the pinion contacts the thrust receiving wall of the pinion shaft by a relative movement with the pinion shaft. Therefore, the pinion is restricted from inclining with respect to the pinion shaft.
Further, a pressing member is provided between the pinion and the pinion shaft at the rear side of the pinion to press the pinion against the detent ring with respect to the pinion shaft. Thus, the vibrations of the pinion against the pinion shaft are suppressed.